Apparatus for testing fuel injection nozzles of compression ignition engines



May 12, 1970 R. s. EMERSON L 87 APPARATUS FOR TESTING FUEL INJECTIONNOZZLES OF COMPRESSION IGNITION ENGINES Filed May 20, 1968 71 All?llVAfT Invenlow, I

A ttorneys I United States Patent 3,511,087 APPARATUS FOR TESTING FUELINJECTION NOZZLES OF COMPRESSION IGNITION ENGINES Reginald S. Emersonand Cecil I. Taylor, both of Tingewick Road, Buckingham,Buckinghamshire, England Filed May 20, 1968, Ser. No. 730,410 Int. Cl.G01m 15/00 U.S. Cl. 73-119 6 Claims ABSTRACT OF THE DISCLOSURE Thisinvention relates to apparatus for testing the fuel injection nozzles ofcompression ignition engines. More specifically, it is concerned withapparatus for testing the inclination or angular position of the sprayhole or holes in such nozzles.

The fuel injection nozzles used in compression ignition enginesgenerally have an axial bore one end of which is connected to a fuelsupply passage and the other end of which terminates in a number ofsmall spray holes in the extreme tip of the nozzle. These spray holesextend from the axis of the bore at a predetermined inclination orangular position so as to ensure that the fuel ejected by the nozzledoes not impinge on vital parts of the combustion chamber of the enginessuch as the cylinder valves and piston. It is therefore important thatthe inclination or attitude of these spray holes be carefully checkedfor accuracy, and the main object of the present invention is to provideapparatus by which such checking can be done in an effective way.

According to the invention, apparatus for testing the fuel injectionnozzles of compression ignition engines comprises nozzle-holding meansfor holding a fuel injection nozzle and a liquid supply passage forsupplying liquid to the nozzle, in which the nozzle-holding means arearranged to so hold the nozzle that it sprays liquid upwards on to avertically-adjustable target whereby the inclination or attitude of thespray hole or holes in the nozzle can be ascertained, the supply ofliquid to the nozzle being effected by liquid supply means which causeliquid to be forced from a container into the said passage leading tothe nozzle by means of pressure exerted on the liquid in the container.

Preferably the apparatus comprises a cylindrical chamber which is openat its upper end and which has a horizontal partition located somewherebetween its upper and lower ends. An axially-movable tubular stem passesup wards through a central hole in the partition and is urged upwards bya spring so as to press against a nozzle to be tested. The nozzle islocated in a hole provided in a bracket or other holder so that itsspray holes are arranged to direct liquid in an upward direction. Thetarget takes the form of an open-ended cylinder provided with a ring ofholes or windows, the target being supported on a ring which isvertically adjustable so that the target can be adjusted vertically inrelation to the nozzle being tested. This allows the target to beadjusted so that the ring of holes or windows provided in it arepositioned to receive the jets of liquid issuing through the spray holesof the nozzle during the testing procedure. As already indicated, liquidis supplied to the nozzle by pressure exerted on 3,51 1,087 Patented May12, 1970 liquid in the cylinder chamber, the pressure being obtained bysupplying air under pressure through a pipe which leads to an inlet inthe lower compartment of the chamber, that is to say the part of thechamber below the partition previously mentioned.

In order that the invention may be thoroughly understood, an example ofapparatus in accordance with it will now be described with reference tothe accompanying drawing which shows the apparatus in vertical section.

The apparatus shown in the drawing comprises a cylindrical chamber 1which is closed at the bottom end and is open. at the top end, thechamber being divided in two by a horizontal partition 2 so as to form aclosed lower compartment 5 and an open upper compartment 6. Thepartition 2 is provided with a central bore 3 and a ring of other holes4, and includes a hollow spigot portion 7 which extends downwards fromthe partition and is provided externally with a liquid filter 8 and aflange 9. A disc-shaped valve 10 surrounds the spigot 7 and is arrangedfor limited axial movement between the bottom face of the partition 2and the flange 9. A tubular stem 11 passes upwards through the bore 3 inthe partition 2, the lower portion of the tubular stem within the hollowspigot 7 having a head portion 12 which is slidable within the spigot.The outer surface of the head portion 12 is provided with knurles so asto provide communication between the spaces above and below the head andto prevent any tendency for the head to seal those spaces from oneanother. It will be seen that the head portion 12 is cup-shaped so as toform an annular duct 13 which communicates through a passage 13a withthe bore 14 of the tubular member 11. A helical spring 15 urges themember 11 upwards towards the open upper end of the chamber 1, and anorifice 16 in the wall of the spigot 7 communicates between the hollowinterior of the spigot and the clean side of the filter 8.

Extending upwards from the partition 2 towards the open end of thechamber 1 are two pillars 17 and 17a. A bracket 18 is verticallyslidable on these two pillars and is provided with several spokes 18acarrying a ring 19 which is provided with a machined recess in which anopen-ended cylindrical target 20 can be rotated by hand. A secondbracket 22 which is also slidable on the pillars 17 and 17a has aconical bore 23 adapted to receive and locate an injector nozzle 24 tobe tested. A pin 25 or other suitable latch locates the bracket 22 onthe pillar 17 in a fixed vertical position, while a removable distancepiece 21 sets the vertical position of the target-supporting ring 19 sothat a ring of holes or windows 26 in the target 20 are brought into thedesired angular relationship with the inclined holes 27 in the injectornozzle 24.

The apparatus also includes an upstanding pipe 28 which communicateswith the closed compartment 5 and which is provided with an orifice 29arranged to direct air under pressure into the open end of an exhaustduct 30. In addition, an air supply duct 31 communicates with the closedcompartment 5 and is provided with a control valve 32 having an open andclosed position as indicated.

The apparatus described above is used in the following manner:

The upper compartment 6 is partially filled with an appropriate liquidtesting medium such as oil to an approximate level indicated at 33. Theoil is poured into the open compartment 6 and then passes through theholes 4 in the partition 2 into the closed compartment 5. When the levelin the closed compartment 5 reaches the valve 10, the valve (having alower specific gravity than the oil) floats up on the surface of the oilso as to close the holes 4.

In order to position the injector to be tested, the pin 25 is withdrawnand the injector-holding bracket 22 re- 3 moved from the pillar or post17. The injector nozzle is then placed over the top of the hollow stem-11 and the bracket 22 replaced on the pillar 17 and pushed down on tothe shoulder 34 on the pillar. The pin 25 is now reinserted. In thisposition the central stem 11 is pushed downwards against the spring 15which thereby exerts an upwardly-directed force through the stem 11 insealing engagement with the injector nozzle. Assuming now that the sprayholes 27 in the injector nozzle to be tested are intended to lie on thesurface of a cone having an included angle of 120, a distance piece 21is selected of such a length that the target holes 26 each subtend anangle of 120 at the apex of the spray holes 27. The control valve 32,hitherto in the closed position, is now moved to the open position sothat air is admitted at a suitable pressure, for example in the regionof 100' lb. per square inch, into the lower compartment 5. As a resultof this air pressure, oil in the compartment passes through the orifice'16 into the interior of the hollow spigot 7, and thence past the knurls12 and through the opening 13a and the bore 14 of the stem 11 into thecentral chamber of the injector nozzle 24. From here the oil passesthrough the spray holes 27, thereby forming jets which impinge on theinner face of the target 20. The target 20 is rotated by hand until eachof the jets passes through a hole or window 26 in the target. If thespray holes of the nozzle are accurate and at the correct angle ofinclination, the jets will all pass through the holes or windows 26. Ifhowever one or other of the jets does not pass through its appropriatewindow, then this will indicate that the particular spray hole or holesis worn or incorrectly formed, or is corroded or partially blocked withcarbon deposits. Irrespective of whether or not the jets of oil passthrough the holes or Windows 26, the oil drops down under gravity andcollects in the lower portion of the upper compartment above thepartition 2.

We have found that the jets of oil impinging either on the target or onthe inner face of the compartment surrounding the target cause aconsiderable mist. This mist is accordingly extracted from thecompartment 6 by being induced up the duct 30 and away from theapparatus by an air jet issuing from the orifice 29 of the pipe 28. Asair from the air supply passage 31 begins to fill the top of the lowercompartment 5, the valve does not drop down since there is now adifferential pressure across it due to the presence of the holes 4 inthe partition 2. The valve 10 therefore remains closed as the oil in thelower compartment 5 is pushed up the bore 14 of the stem 11. At thetermination of the test when it is decided whether the injector nozzle24 has passed the test or not, the aircontrol valve 32 is returned tothe closed position and the air pressure in the compartment 5 isexhausted through the orifice 29. Once the pressure in the compartment 5has fallen to atmospheric pressure there is no longer any differentialpressure acting across the valve 10 so that it therefore drops on to theshoulder 9 of the spigot 7. The oil contained in the compartment 6 nowpasses downwards through the holes 4 and refills the lower compartment 5until the valve 10- once more floats and blocks the holes 4.

It is to be noted that, if the valve 32 is moved to the open positionwhen no injector nozzle is fitted, the delivery of oil through the bore;14 of the stem 11 is prevented by the spring which causes the enlargedlower end of the stem to abut the underside of the partion 2, therebypreventing any oil from passing through the opening 13a and out of thetop of the stem.

Although the target is shown as having only one ring of holes 26, inpractice it will have two or more rings of holes at different levelswith the rings having different numbers of holes. Preferably there is atleast one ring of holes which is spaced the same distance from the upperend of the target as the holes 26 are from the lower end. This enables asingle target to be suitable for at least two different forms ofinjector nozzle, the target being simply turned upside down. Further, analternative site 35 and 36 is provided for the distance piece 21 which,in conjunction with two further rows of holes in the target, providesfor two more types of injector nozzle by locating the target at adifferent axial position. Other alternative sites for the distance piece21 can also be provided, or use can be made of a set of distance piecesof different lengths.

It will therefore be seen that the apparatus described above is bothversatile and simple to use and operate. The use of air pressure toeffect the supply of liquid to the injector nozzle is simpler and givesa smoother flow than a mechanical pump, although it will of course beappreciated that mechanical pressure provided for example by a pistoncan be used instead of air to apply pressure to the liquid in order todisplace it from the compartment 5.

Another practical advantage is that the injector nozzle under testsprays upwards and is easy to see. Moreover, the tip of the nozzle isreadily accessible for cleaning with a soft wire brush while spraying isin progress. Thus, it may well be found that a nozzle under test whichdoes not function properly at first is subsequently found to beperfectly in order after it has been cleaned by a soft wire brush. Inthis way the inadvertent discarding of a good injector nozzle isprevented.

Finally, the use of an axially-adjustable and rotatable target 20 havingone or more rings of windows or holes 26 allows many different types ofinjector nozzle to be tested on the same apparatus. This is important asthe spray holes of injector nozzles can be at many differentinclinations according to the design of the engine or engines with whichthe injectors are used.

It is to be understood that the specific apparatus described above isgiven by way of example only and that the scope of the invention is notto be limited to that particular construction but is defined solely bythe appended claims.

We claim:

1. Apparatus for testing the inclination of inclined spray holes in thefuel injection nozzles of compression iginition engines, said apparatuscomprising, a cylindriwl chamber which is open at its upper end and hasa transverse partition located between its upper and lower ends,nozzle-holding means arranged above the said transverse partition andadapted to hold a fuel injection nozzle So that the nozzle pointsupwardly, a liquid supply passage in the form of a tubular stem passingupwards through a central hole in the partition and adapted to supplyliquid to a nozzle from the space in the chamber below the partitionwhen the nozzle is held in said nozzleholding means, the said tubularstem being axially movable and being urged upwards by a spring so as topress against a nozzle to be tested, a Vertically-adjustable targetextending above the level of the nozzle-holding means whereby liquidissuing under pressure from the inclined spray holes of the nozzleimpinges on said target, and means for applying pressure to a liquid inthe space in the chamber below the partition so as to cause the liquidto be forced from said space into said liquid supply passage and thenceinto the nozzle to be tested.

2. Apparatus according to claim 1, in which said pressure-applying meansinclude an air supply passage leading to an inlet in that part of thechamber below the transverse partition so that air pressure can be usedto force liquid out of the chamber space below the partition into thetubular stem.

3. Apparatus according to claim 1, in which the target takes the form ofan open-ended cylinder provided with a ring of windows which receive thejets of liquid issuing through the spray holes of the nozzle during thetesting procedure.

4. Apparatus according to claim 3, in which the target is rotatablysupported on a ring which is vertically adjustable so that the targetcan be adjusted vertically in relation to the nozzle being tested andcan be ro-' tated in order to bring the windows into line with the side,the hole or holes being opened and closed by a spray holes of a nozzleto be tested. disc valve which floats in the space below the partition.

5. Apparatus according to claim 1, in which the lower end of the tubularstem has a head poriton which References Cited slides within a hollowspigot extending downwards from th trans e s p t't' th h 110w sp'got b 5UNITED STATES PATENTS e v r e ar 1 ion, e o 1 eing in communication withthe interior of that part of the cy- 2629255 2/1953 Harmdge' lindricalchamber which lies below the partition and being surrounded by a liquidfilter. OTHER REFERENCES 6. Apparatus according to claim 1, in which thetrans- 10 verse partition has one or more holes for the passage ofliquid from one side of the partition to the other JERRY MYRACLE,Pflmafy EXamlner 1,104,198 4/1961 Germany.

